Not Following This Tutorial At All...

I have been working on a wizard interface on the application I am building.  I am down to the last step/s, which unlike all the previous steps is all in one table. 

To assist I have been reading and trying to emulate this tutorial I found as it looks like the approach I need for this specific step/s.  http://www.binaryintellect.net/articles/9a5fe277-6e7e-43e5-8408-a28ff5be7801.aspx

I reasonably quickly realised there is some issues here I don't understand, and some of this looks out of date.

What I don't get.  I have a model:

 public class QuoteDetails
    {
        public int QuoteDetailsID { get; set; }

        public int QuoteID { get; set; }
        [Display(Name = "Distance in km")]
        public decimal Distance { get; set; }

        [Display(Name = "Allowed Hours")]

        public double AllowedHours { get; set; }

        [Display(Name = "Hourly Charge Rate")]
        [DataType(DataType.Currency)]
        public decimal HourlyCharge { get; set; }

        [Display(Name = "Calculated Cost")]
        [DataType(DataType.Currency)]
        public decimal CalculatedCost { get; set; }

        [Display(Name = "Margin to Apply")]
        public double Margin { get; set; }

        [Display(Name = "Quote Introduction")]
        public string QuoteIntroduction { get; set; }

        [Display(Name = "Quote Closing")]
        public string QuoteConclusion { get; set; }

        [Display(Name = "Quote Submit Date")]
        [DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:D}")]
        public DateTime QuoteDate { get; set; }

        public Quote Quote { get; set; }

        public ICollection<QuoteFollowUp> QuoteFollowUp { get; set; }

Using the examples in the tutorial it suggests breaking this out to View Models.

I haven't worked with view models before.  All the other tutorials I have worked with work direct with data.  I have seen them talked about and been content to know they are there, but without a specific need I thought I would avoid them...until now.

So I set up the view model for the first step:

using System.ComponentModel.DataAnnotations;

namespace Eva804.ViewModel
{
    public class SalesQuoteStep1
    {
        [Required]
        public int QuoteID { get; set; }

        [Display(Name = "Distance in km")]
        public decimal Distance { get; set; }

        [Display(Name = "Allowed Hours")]
        public double AllowedHours { get; set; }
    }
}

What I am finding somewhat confusing here is:

How does the view model know we are pointing to the Quote Details model? 

I would have assumed a using statement is required.  Why isn't it?

Then the tutorial suggests using session state to hold the data temporarily.  This sounds like a good idea and looks like a good idea.  However the tutorial examples use Session.etc.  This is changed in Asp.Net core.

I found through readings how to set up the sessions within Asp.Net Core however I am now confused with the next step in the tutorial.  From Tutorial:

private Customer GetCustomer()
{
  if (Session["customer"] == null)
  {
    Session["customer"] = new Customer();
  }
  return (Customer)Session["customer"];
}

Okay, so in ASP.Net Core we use

 HttpContext.Session.SetString("SalesQuote", "quoteID");

As I understand it, and I may have this wrong, this initiates a session and gives a name SalesQuote and stores quoteID in it. Have I got this correct?

I am not sure how to go about checking if the session exists as in the tutorial?

Is there a better tutorial using a similar approach?

I have emboldened the questions as they are scattered in the post.

Thanks in advance